Earnings Per Share (Details) - USD ($) shares in Millions, $ in Millions	3 Months Ended
Mar. 31, 2018	Mar. 31, 2017
Earnings Per Share [Abstract]
Average common shares outstanding (in shares)	126.5	125.7
Effect of dilutive securities - share-based compensation (in shares)	0.0	1.7
Average shares for diluted computations (in shares)	126.5	127.4
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Income (Loss) from Continuing Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest	$ (112.3)	$ 10.3
Potentially dilutive shares (in shares)	6.1	2.9
Other Preferred Stock Dividends and Adjustments	$ 0.0	$ (0.9)
Income (Loss) From Continuing Operations Available To Shareholders	$ (112.3)	$ 9.4
Share Options and Appreciation Rights [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potentially dilutive shares (in shares)	1.5	1.5
Novested Restricted Shares and Restricted Share Units [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potentially dilutive shares (in shares)	4.6	1.4

Income (Loss) From Continuing Operations Available To Shareholders

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Securities (including those issuable pursuant to contingent stock agreements) that could potentially dilute basic earnings per share (EPS) or earnings per unit (EPU) in the future that were not included in the computation of diluted EPS or EPU because to do so would increase EPS or EPU amounts or decrease loss per share or unit amounts for the period presented.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Amount after tax of income (loss) from continuing operations including portion attributable to the noncontrolling interest.

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Additional shares included in the calculation of diluted EPS as a result of the potentially dilutive effect of share based payment arrangements using the treasury stock method.

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Amount of preferred stock dividends and adjustments classified as other.

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The average number of shares or units issued and outstanding that are used in calculating diluted EPS or earnings per unit (EPU), determined based on the timing of issuance of shares or units in the period.

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Number of [basic] shares or units, after adjustment for contingently issuable shares or units and other shares or units not deemed outstanding, determined by relating the portion of time within a reporting period that common shares or units have been outstanding to the total time in that period.

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